1. Field of the Invention
The present invention relates to an image processing method, and more particularly, to a method for performing a color analysis operation.
2. Description of the Prior Art
Automated identification and verification of known currency bills is a practical application when applied to retail and business environments. Electronic verification of known bill types helps to increase security in monetary transactions, and also prevents vendors from receiving counterfeit currencies. The currency detectors available today typically scan an image of a sample currency, from which a series of tests is performed in order to determine the validity of the sample. The tests used can include the identification of known currency sections or landmarks, holograms, reflective areas, printing patterns, and texture patterns.
Improvements in graphics and image duplication systems, which can include scanners, digital color copiers, and printing machinery and apparatuses, has also contributed to the increase in illegal counterfeit reproduction of various items. Counterfeiters nowadays commonly attempt to reproduce monetary banknotes such as currencies, stocks, bonds, and other valuable items for personal gain and profit. The task of distinguishing and discerning between legitimate items and copied fakes is becoming increasingly difficult as printing and reproduction improvements allow copiers to reproduce banknotes that are virtually identical to legitimate ones. Therefore, there is a need to be able to effectively and precisely discern and distinguish monetary banknotes from authentic ones.
In addition to the increasing difficulties in identifying legitimate currency bills, one more problem is the desire to scan sample currencies from images that are larger than the sample currency being scanned. However, doing this introduces more problems as the bills may be presented on arbitrary backgrounds, and may have variations in shift and rotation. Many currency detectors today generally only scan one bill at a time, and only scan the immediate area of the bill in order to omit the need to consider the background, rotation, and alignment of the bill. In addition, if the note is scanned while embedded with a complicated image background, it may be very difficult to distinguish the actual note from the image background. The image background may also provide additional noise and/or patterns to complicate the detection process and introduce irregularities and errors. It is needless to say that without the proper identification of a currency note from its image background, while having various offsets and rotations, optimal conditions for accurate currency detection can not be met.